1. Field of the Invention
The present invention relates to a process cartridge for use in an image forming apparatus, such as for example an electrophotographic copying machine. More particularly, the present invention relates to a process cartridge in which a photoconductor unit containing a rotatably mounted photoconductor drum and a developing unit containing a rotatably mounted developing roller arc connected together, an image forming apparatus using this process cartridge, and a method of manufacturing the process cartridge.
2. Discussion of the Background
Image forming apparatuses, such as for example copying machines, printers, and the like, which combine in one case a process cartridge with a photoconductor unit including a photoconductor drum and a developing unit including a developing roller are widespread in the market. When the lifetime of either the photoconductor drum or the developing roller has expired in such image forming apparatuses, the entire process cartridge containing the photoconductor unit including the photoconductor drum and the developing unit including the developing roller is replaced with a new process cartridge, thus replacing the used photoconductor drum and developing roller.
Further, as a method of assembling the aforementioned process cartridge, there is a known method by which the photoconductor unit and the developing unit are individually assembled to improve the efficiency of the assembly work for the photoconductor unit and the developing unit. The photoconductor unit and the developing unit are connected together to each other at the final stage of assembling the process cartridge.
Generally, in the aforementioned process cartridge, a connecting plate is used to connect and fix the photoconductor unit to the developing unit. The connecting plate increases the accuracy in setting a distance between the photoconductor drum and the developing roller.
Also, another method of assembling a process cartridge has been proposed for connecting the photoconductor drum and the developing roller together, in which a central axis of the photoconductor drum and that of the developing roller are accurately positioned by a jig. The photoconductor unit and the developing unit are fixed with screws while being positioned by the jig.
A process cartridge in which the photoconductor unit and the developing unit are connected together using the connecting plate poses a problem in that the connecting plate increases the number of parts and thereby increases the manufacturing cost. In addition, the number of steps involved in assembling the process cartridge increases when the connecting plate is used.
In this process cartridge in which the photoconductor unit and the developing unit are connected with each other using the jig, a significantly high accuracy of the distance between the photoconductor drum and the developing roller can be obtained without increasing the number of parts. However, the number of steps involved in assembling the process cartridge increases when the jig is used.